Formation and retention of cotinine during placental transfer of nicotine in human placental cotyledon.

Maternal smoking during pregnancy causes reduction of fetal breathing movements, an effect attributed to nicotine in fetal blood. Nicotine is metabolized to cotinine which has a long plasma half-life and exhibits slow clearance across membrane barriers. It is also known to activate placental phospholipase-A2-like enzymes, resulting in formation of prostaglandins.

Hyperhomocysteinemia: a risk factor for placental abruption or infarction.

Objective: To establish the prevalence of hyperhomocysteinemia in women with placental abruption or infarction.

Design: Forty-six women with normal pregnancy outcome (controls) and 84 women with placental abruption or infarction (study group) were selected, and studied in the non-pregnant state. Homocysteine metabolism was investigated by a standardized oral methionine loading test.